President Trump confirmed Friday that he's being investigated for firing James Comey as FBI director, and appeared to attack Deputy Attorney General Rod Rosenstein, who advised the president that the the FBI was unlikely to regain the trust of Americans and of Congress with Comey leading the agency.

The president conveyed the message on Twitter.

I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt

Rosenstein wrote a memo to the president that was intensely critical of Comey and implicitly recommended his removal. About a week after Comey was fired last month, however, Rosenstein appointed former FBI Director Robert Mueller as a special counsel at the Justice Department to oversee the federal investigation into Russia's efforts to meddle in the 2016 U.S. election. Rosenstein is in charge of hiring and firing because Attorney General Jeff Sessions recused himself from the Russia probe.

Late Thursday, Rosenstein issued an unusual statement about anonymous sources.

"Americans should exercise caution before accepting as true any stories attributed to anonymous 'officials,' particularly when they do not identify the country – let alone the branch or agency of government – with which the alleged sources supposedly are affiliated," he said. "Americans should be skeptical about anonymous allegations. The Department of Justice has a long-established policy to neither confirm nor deny such allegations."

Although Rosenstein's statement did not reference a specific story, it was released a few hours after the Washington Post published a story stating that the special counsel is investigating the business dealings of Mr. Trump's son-in-law and top adviser Jared Kushner. That story relied on "U.S. officials familiar with the matter."

The president's tweets Friday come as Mueller is reviewing and collecting evidence on whether Mr. Trump or anyone else in his administration was or is trying to end the investigation into former National Security Adviser Gen. Michael Flynn, CBS News' Paula Reid confirmed, citing a source close to the investigation.

Rosenstein testified at a Senate hearing earlier this week that he sees no reason to fire Mueller. His comment came after a friend of President Trump's, Newmax CEO Chris Ruddy, said Monday that the president is considering firing the special counsel.

Meanwhile, Sessions testified the same day about his role in the firing of Comey and why he recused himself.

(AP Photo/Evan Vucci, File). FILE - In this March 15, 2018, file photo, President Donald Trump talks with reporters during a meeting in the Oval Office of the White House in Washington. Trump is questioning the impartiality of Robert Mueller's investig...

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